Method:1. Heat 1 tsp oil in a large kadai.2. Add the masala ingredients and fry for 2 to 3 minutes.3. Remove and grind to a fine powder.4. In a bowl, mix the curd, besan flour, sugar and salt together.5. Whisk till well blended.6. In an another pan (or the same pan used for frying masala), add turmeric, green chillies and grated ginger with 1 cup of water.7. Bring to boil.8. Add the ashgourd pieces and cover pan.9. Simmer for 5 to 7 minutes till tender.10. Lower heat and pour in the curd mixture.11. Simmer uncovered for 3 to 4 minutes, stirring from time to time.12. Add the masala powder and mix well.13. Simmer for one more minute.14. Heat oil for tempering in a small pan.15. Add the tempering ingredients and fry.16. When mustard seeds start spluttering, add it to the pulusu.17. Serve hot with plain rice.